C# / .NET - check if number is odd

In this short article, we would like to show how check if number is odd using C# / .NET.

Quick solution:

int number = 5;

if (number % 2 != 0)
{
    // ...
}

Odd numbers:

... -7  -5  -3  -1   1   3   5   7 ...

Practical example

using System;

public class Program
{
    public static void Main(String[] args)
	{    
		Console.WriteLine( NumberUtils.IsOdd(0) );   // false
		Console.WriteLine( NumberUtils.IsOdd(1) );   // true      // odd
		Console.WriteLine( NumberUtils.IsOdd(2) );   // false
		Console.WriteLine( NumberUtils.IsOdd(3) );   // true      // odd
		Console.WriteLine( NumberUtils.IsOdd(4) );   // false
		Console.WriteLine( NumberUtils.IsOdd(5) );   // true      // odd

		Console.WriteLine( NumberUtils.IsOdd(-1) );  // true      // odd
		Console.WriteLine( NumberUtils.IsOdd(-2) );  // false
		Console.WriteLine( NumberUtils.IsOdd(-3) );  // true      // odd
		Console.WriteLine( NumberUtils.IsOdd(-4) );  // false
		Console.WriteLine( NumberUtils.IsOdd(-5) );  // true      // odd
    }
}

public class NumberUtils
{
	public static bool IsOdd(int number)
	{
		return number % 2 != 0;
	}
}

Alternative solution

In this section, you can find solution that uses bitwise operator.

using System;

public class Program
{
    public static void Main(String[] args)
	{    
		Console.WriteLine( NumberUtils.IsOdd(0) );   // false
		Console.WriteLine( NumberUtils.IsOdd(1) );   // true      // odd
		Console.WriteLine( NumberUtils.IsOdd(2) );   // false
		Console.WriteLine( NumberUtils.IsOdd(3) );   // true      // odd
		Console.WriteLine( NumberUtils.IsOdd(4) );   // false
		Console.WriteLine( NumberUtils.IsOdd(5) );   // true      // odd

		Console.WriteLine( NumberUtils.IsOdd(-1) );  // true      // odd
		Console.WriteLine( NumberUtils.IsOdd(-2) );  // false
		Console.WriteLine( NumberUtils.IsOdd(-3) );  // true      // odd
		Console.WriteLine( NumberUtils.IsOdd(-4) );  // false
		Console.WriteLine( NumberUtils.IsOdd(-5) );  // true      // odd
    }
}

public class NumberUtils
{
	public static bool IsOdd(int number)
	{
		return (number & 1) != 0;
	}
}

See also

1. C# / .NET - check if number is even